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IBDP Biology: Methicillin Resistant Staphylococcus aureus (MRSA)

Methicillin Resistant Staphylococcus aureus

August 15, 2022

In this topic of IBDP Biology, we will learn about Methicillin Resistant Staphylococcus aureus (MRSA).

MRSA

  • Methicillin Resistant Staphylococcus aureus.
  • 1 in 3 carries SA on the surface of skin, or in our nose, without developing an infection.
  • However, if SA bacteria get into the body through a break in the skin they can cause infections such as boils, abscesses, or impetigo.
  • If they get into the bloodstream they can cause more serious infections.
  • Most SA infections can be treated with antibiotics such as methicillin.
  • However, SA is becoming increasingly resistant to most commonly used antibiotics.
  • MRSA is no more infectious than other types of SA bacteria.
  • However, MRSA infections are more difficult to treat due to the antibiotic-resistance of the bacteria.
  • When bacteria encounter an antibiotic, such as methicillin, some of the bacteria may survive. Some bacteria mutate to develop a resistance to the antibiotic.
  • The surviving antibiotic-resistant bacteria can multiply.

Spread

  • When it comes to IBDP Biology,  MRSA bacteria is usually spread through person-to-person contact with someone who has an MRSA infection, or who is colonised by the bacteria.
  • It can also spread through contact with towels and sheets.
  • MRSA infections are most common in people who are already in hospital.
  • Those in hospital are more likely to develop MRSA infections.
  • Exposure to antibiotics is more common.
  • Those who are most at risk of MRSA include those who have:
    • A weakened immune system, such as the elderly, newborn babies, or those with a long-term health condition such as diabetes, cancer or HIV/AIDS.
    • An entry point for the bacteria to get into their body, such as a surgical wound, a catheter, or an intravenous tube.

Symptoms

  • Most SA infections are skin infections.
  • If SA bacteria are able to enter the bloodstream they can affect almost any part of the body. They can cause:
    • septicaemia (blood poisoning),
    • septic shock (widespread infection of the blood that leads to a fall in blood pressure and organ failure),
    • severe joint problems (septic arthritis),
    • bone marrow infection (osteomyelitis),
    • internal abscesses anywhere within the body,
    • of the tissues that surround the brain and spinal cord (meningitis),
    • infection (pneumonia), and 
    • infection of the heart lining (endocarditis)

Prevention

  • Wash your hands thoroughly before and after visiting someone in hospital.
  • Hospital staff should maintain very high standards of hygiene.
  • Before and after caring for any patient, hospital staff should make sure they have thoroughly washed and dried their hands.
  • Use fast-acting, special antiseptic solutions, like alcohol rubs or gels.
  • When it comes to IBDP Biology,  staff should wear disposable gloves when they have physical contact with open wounds.

That's the end of this topic.